Denys Petau, a Jesuit scholar, better known as Dionysius Petavius, was born at Orleans on the 21st of August 1583. Educated at Paris University, he came under the influence of Isaac Scaliger, who directed his attention towards the obscurer fathers of the Church. In 1603 he was appointed to a lectureship at the university of Bourges, but resigned his place two years later, in order to enter the Society of Jesus. For many years he was professor of divinity at the Collège de Clermont, the chief Jesuit establishment in Paris; there he died on the 11th of December 1652. He was one of the most brilliant scholars in a learned age. Carrying on and improving the chronological labors of Scaliger, he published in 1627 an Opus de doctrina temporum, which has been often reprinted. An abridgment of this work, Rationarium temporum, was translated into French and English, and has been brought down in a reprint in 1849. But Petau's eminence chiefly rests on his vast, but unfinished, De theologicis dogmatibus, the first systematic attempt ever made to treat the development of Christian doctrine from the historical point of view.